Remove PartialOrd implementation for ScalarValue

[connortsui20]

Summary

This might help with #7699, but it might not. I made the changes though so here we go.

Removes the PartialOrd implementation for ScalarValue, ensuring that we are only able to compare Scalars which carry a DType.

API Changes

Removes the PartialOrd impl.

Testing

Existing tests should suffice since this just moves some logic around.

[codspeed-hq]

Merging this PR will degrade performance by 27.25%

⚠️ Unknown Walltime execution environment detected

Using the Walltime instrument on standard Hosted Runners will lead to inconsistent data.

For the most accurate results, we recommend using CodSpeed Macro Runners: bare-metal machines fine-tuned for performance measurement consistency.

⚠️ Different runtime environments detected

Some benchmarks with significant performance changes were compared across different runtime environments,
which may affect the accuracy of the results.

Open the report in CodSpeed to investigate

⚡ 2 improved benchmarks
❌ 3 regressed benchmarks
✅ 1193 untouched benchmarks

⚠️ Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
⚡	WallTime	runend[10M_i32_runlen_100000]	130 µs	92.2 µs	+41.11%
❌	WallTime	runend[10M_i32_runlen_1000]	98.3 µs	135.2 µs	-27.25%
❌	WallTime	10M_10%[1000000]	133.5 µs	161.1 µs	-17.14%
⚡	WallTime	10M_50%[5000000]	192.3 µs	156.4 µs	+22.89%
❌	WallTime	10M_90%[10000000]	198.5 µs	225.9 µs	-12.14%

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_{Comparing ct/sv-no-derive (024ac65) with develop (deb7de0)}